The photos show a current-generation Mustang with what looks to be a new center stack and an independent rear suspension setup. The interior is far from finished, but it's equipped with a tachometer with a 6,500-rpm redline. The Ford Focus ST also redlines at 6,500 rpm, and what appears to be a front-mounted intercooler lends credence to the suspicion that the mules are testing with the ST's forced-induction 2.0-liter EcoBoost engine.

Autoweekreported back in January that an EcoBoost engine was a near-certainty for the next Mustang. We're a long way from seeing a final car, but this mule certainly confirms that Ford is heading in a new direction with the Mustang.